I think having a cassette for an emergency rudder
installed prior to a long voyage is a very good idea. That is what I will do for my boat. I think it is better to have a fixed gudgeon bracket (to hold the emergency
rudder) already installed on the boat along with the pintles already in a kit (with bolts and other needed bits). Heavy weather
makes use of anything difficult on a boat, so I would prefer to have some of the key parts
already installed, securely fitted, and ready to use in minimal time.
Some of the wind vane
manufacturer's have some proposed uses of their vanes or add on features (e.g. Monitor
has an optional add on emergency rudder
The Singlehanded Sailing Society in San Francisco
has a website with many different resources available (articles, tips, etc.). This page has links to a lot of information that singlehanded (or short handed) cruisers may find interesting (I did).
Resources | Singlehanded Sailing Society
One document is an illustrated 2014 presentation with lots of technical specs on how Autopilots work and typical causes of failure. I found this interesting to read, and while it is not directly related to emergency rudders, I think some of the info is worth seeing. http://sfbaysss.net/resource/doc/SSS...lot_011314.pdf
Another document that features some illustrations and technical discussion of a few types of possible emergency rudders or steering
And there is even a paper on using a "soft rudder" (made of sailcloth) that can be made and used in an emergency.